Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava ...Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava mash under different pH conditions. Final ethanol concentrations increased when undissociated propanoic acid was <30.0 mmol·L-1 . Propanoic acid, however, stimulated ethanol production, as much as 7.6% under proper conditions, but ethanol fermentation was completely inhibited when undissociated acid was >53.2 mmol·L-1 . Therefore, the potential inhibitory effect of propanoic acid on ethanol fermentation may be avoided by controlling the undissociated acid concentrations through elevated medium pH. Biomass and glycerol production decreased with propanoic acid in the medium, partly contributing to increased ethanol concentration.展开更多
The biosorption of Cd2＋ and CH2＋ onto the immobilized Saccharomyces cerevisiae （S. cerevisiae） was investigated in this study. Adsorption kinetics, isotherms and the effect ofpH were studied. The results indicated...The biosorption of Cd2＋ and CH2＋ onto the immobilized Saccharomyces cerevisiae （S. cerevisiae） was investigated in this study. Adsorption kinetics, isotherms and the effect ofpH were studied. The results indicated that the biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae was fast at initial stage and then became slow. The maximum biosorption of heavy metal ions on immobilized S. cerevisiae were observed at pH 4 for Cde＋ and Cu^2＋. by the pseudo-second-order model described the sorption kinetic data well according to the high correlation coefficient （R2） obtained. The biosorption isotherm was fitted well by the Langmuir model, indicating possible mono-layer biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae. Moreover, the immobilized S. cerevisiae after the sorption of Cd^2＋ and Cu^2＋ could be regenerated and reused.展开更多
A robust and versatile tool for multigene pathway assembly is a key to the biosynthesis of high- value chemicals. Here we report the rapid construction of biosynthetic pathways in Saccharomyces cerevisiae using a mark...A robust and versatile tool for multigene pathway assembly is a key to the biosynthesis of high- value chemicals. Here we report the rapid construction of biosynthetic pathways in Saccharomyces cerevisiae using a marker recyclable integrative toolbox （pUMRI） devel- oped in our research group, which has features of ready-to- use, convenient marker recycling, arbitrary element replacement, shuttle plasmid, auxotrophic marker inde- pendence, GAL regulation, and decentralized assembly. Functional isoprenoid biosynthesis pathways containing 4-11 genes with lengths ranging from -10 to -22 kb were assembled using this toolbox within 1-5 rounds of reiterative recombination. In combination with GAL- regulated metabolic engineering, high production of isoprenoids （e.g., 16.3 mg.g-1 dcw carotenoids）was achieved. These results demonstrate the wide range of application and the efficiency of the pUMRI toolbox in multigene pathway construction of S. cerevisiae.展开更多
酿酒酵母BUV094经发酵培养后,离心收集菌体,将菌体用甲苯法破壁得到粗酶液,粗酶液经调节PH除杂蛋白,丙酮二次沉淀三步纯化工艺,得到纯化的SOD,其比活为1015U/mg,收率为65.2%。PAGE电泳后的活性染色显示,酵母超氧化物歧化酶具四条同功酶...酿酒酵母BUV094经发酵培养后,离心收集菌体,将菌体用甲苯法破壁得到粗酶液,粗酶液经调节PH除杂蛋白,丙酮二次沉淀三步纯化工艺,得到纯化的SOD,其比活为1015U/mg,收率为65.2%。PAGE电泳后的活性染色显示,酵母超氧化物歧化酶具四条同功酶。该样品经K C N,H2O2,氯仿—乙醇抑制试验,酶类型为Cu/ZnSOD。展开更多
研究了高压脉冲电场(pulsed electric field,PEF)对接种于胡萝卜汁中酿酒酵母(Saccharomyces cerevisiae,CGMCC2.604)的杀菌效果并进行了模型分析。结果表明,随电场强度和脉冲时间增加,PEF对酿酒酵母的杀灭效果增强,25kV/cm、2173μs时...研究了高压脉冲电场(pulsed electric field,PEF)对接种于胡萝卜汁中酿酒酵母(Saccharomyces cerevisiae,CGMCC2.604)的杀菌效果并进行了模型分析。结果表明,随电场强度和脉冲时间增加,PEF对酿酒酵母的杀灭效果增强,25kV/cm、2173μs时酿酒酵母降低了4.5个对数。Weibull模型和Log-Logistic模型均能很好的拟合PEF处理酿酒酵母的失活曲线,模型评价参数(Af,Bf,SS,RMSE和R2)分析表明,Log-Logistic模型比Weibull模型能更好地拟合PEF处理下酿酒酵母失活动力学变化。展开更多
African swine fever virus(ASFV)infects domestic pigs and European wild boars with strong,hemorrhagic and high mortality.The primary cellular targets of ASFV is the porcine macrophages.Up to now,no commercial vaccine o...African swine fever virus(ASFV)infects domestic pigs and European wild boars with strong,hemorrhagic and high mortality.The primary cellular targets of ASFV is the porcine macrophages.Up to now,no commercial vaccine or effective treatment available to control the disease.In this study,three recombinant Saccharomyces cerevisiae(S.cerevisiae)strains expressing fused ASFV proteins-porcine Ig heavy chains were constructed and the immunogenicity of the S.cerevisiae-vectored cocktail ASFV feeding vaccine was further evaluated.To be specific,the P30-Fcγand P54-Fcαfusion proteins displaying on surface of S.cerevisiae cells were produced by fusing the Fc fragment of porcine immunoglobulin IgG1 or IgA1 with p30 or p54 gene of ASFV respectively.The recombinant P30-Fcγand P54-Fcαfusion proteins expressed by S.cerevisiae were verified by Western blotting,flow cytometry and immunofluorescence assay.Porcine immunoglobulin Fc fragment fused P30/P54 proteins elicited P30/P54-specific antibody production and induced higher mucosal immunity in swine.The absorption and phagocytosis of recombinant S.cerevisiae strains in IPEC-J2 cells or porcine alveolar macrophage(PAM)cells were significantly enhanced,too.Here,we introduce a kind of cheap and safe oral S.cerevisiae-vectored vaccine,which could activate the specific mucosal immunity for controlling ASFV infection.展开更多
Currently,the establishment of synthetic microbial consortia with rational strategies has gained extensive attention,becoming one of the important frontiers of synthetic biology.Systems biology can offer insights into...Currently,the establishment of synthetic microbial consortia with rational strategies has gained extensive attention,becoming one of the important frontiers of synthetic biology.Systems biology can offer insights into the design and construction of synthetic microbial consortia.Taking the high-efficiency production of 2-keto-L-gulonic acid(2-KLG)as an example,we constructed a synthetic microbial consortium“Saccharomyces cerevisiae-Ketogulonigenium vulgare”based on systems biology analysis.In the consortium,K.vulgare was the 2-KLG pro-ducing strain,and S.cerevisiae acted as the helper strain.Comparative transcriptomic analysis was performed on an engineered S.cerevisiae(VTC2)and a wild-type S.cerevisiae BY4741.The results showed that the up-regulated genes in VTC2,compared with BY4741,were mainly involved in glycolysis,TCA cycle,purine metabolism,and biosynthesis of amino acids,B vitamins,and antioxidant proteases,all of which play important roles in pro-moting the growth of K.vulgare.Furthermore,Vitamin C produced by VTC2 could further relieve the oxidative stress in the environment to increase the production of 2-KLG.Therefore,VTC2 would be of great advantage in working with K.vulgare.Thus,the synthetic microbial consortium"VTC2-K.vulgare"was constructed based on transcriptomics analyses,and the accumulation of 2-KLG was increased by 1.49-fold compared with that of mono-cultured K.vulgare,reaching 13.2±0.52 g/L.In addition,the increased production of 2-KLG was accompanied by the up-regulated activities of superoxide dismutase and catalase in the medium and the up-regulated oxidative stress-related genes(sod,cat and gpd)in K.vulgare.The results indicated that the oxida-tive stress in the synthetic microbial consortium was efficiently reduced.Thus,systems analysis confirmed a favorable symbiotic relationship between microorganisms,providing guidance for further engineering synthetic consortia.展开更多
基金Supported by the National High Technology Research and Development Program of China (2008AA10Z338)
文摘Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava mash under different pH conditions. Final ethanol concentrations increased when undissociated propanoic acid was <30.0 mmol·L-1 . Propanoic acid, however, stimulated ethanol production, as much as 7.6% under proper conditions, but ethanol fermentation was completely inhibited when undissociated acid was >53.2 mmol·L-1 . Therefore, the potential inhibitory effect of propanoic acid on ethanol fermentation may be avoided by controlling the undissociated acid concentrations through elevated medium pH. Biomass and glycerol production decreased with propanoic acid in the medium, partly contributing to increased ethanol concentration.
文摘The biosorption of Cd2＋ and CH2＋ onto the immobilized Saccharomyces cerevisiae （S. cerevisiae） was investigated in this study. Adsorption kinetics, isotherms and the effect ofpH were studied. The results indicated that the biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae was fast at initial stage and then became slow. The maximum biosorption of heavy metal ions on immobilized S. cerevisiae were observed at pH 4 for Cde＋ and Cu^2＋. by the pseudo-second-order model described the sorption kinetic data well according to the high correlation coefficient （R2） obtained. The biosorption isotherm was fitted well by the Langmuir model, indicating possible mono-layer biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae. Moreover, the immobilized S. cerevisiae after the sorption of Cd^2＋ and Cu^2＋ could be regenerated and reused.
基金This work was financially supported by the National Natural Science Foundation of China （Grant Nos. 21406196 and 21576234）, Zhejiang Provincial Natural Science Foundation of China （Grant No. LQI4B060005）, and Qianiiang Talents Project.
文摘A robust and versatile tool for multigene pathway assembly is a key to the biosynthesis of high- value chemicals. Here we report the rapid construction of biosynthetic pathways in Saccharomyces cerevisiae using a marker recyclable integrative toolbox （pUMRI） devel- oped in our research group, which has features of ready-to- use, convenient marker recycling, arbitrary element replacement, shuttle plasmid, auxotrophic marker inde- pendence, GAL regulation, and decentralized assembly. Functional isoprenoid biosynthesis pathways containing 4-11 genes with lengths ranging from -10 to -22 kb were assembled using this toolbox within 1-5 rounds of reiterative recombination. In combination with GAL- regulated metabolic engineering, high production of isoprenoids （e.g., 16.3 mg.g-1 dcw carotenoids）was achieved. These results demonstrate the wide range of application and the efficiency of the pUMRI toolbox in multigene pathway construction of S. cerevisiae.
文摘酿酒酵母BUV094经发酵培养后,离心收集菌体,将菌体用甲苯法破壁得到粗酶液,粗酶液经调节PH除杂蛋白,丙酮二次沉淀三步纯化工艺,得到纯化的SOD,其比活为1015U/mg,收率为65.2%。PAGE电泳后的活性染色显示,酵母超氧化物歧化酶具四条同功酶。该样品经K C N,H2O2,氯仿—乙醇抑制试验,酶类型为Cu/ZnSOD。
文摘研究了高压脉冲电场(pulsed electric field,PEF)对接种于胡萝卜汁中酿酒酵母(Saccharomyces cerevisiae,CGMCC2.604)的杀菌效果并进行了模型分析。结果表明,随电场强度和脉冲时间增加,PEF对酿酒酵母的杀灭效果增强,25kV/cm、2173μs时酿酒酵母降低了4.5个对数。Weibull模型和Log-Logistic模型均能很好的拟合PEF处理酿酒酵母的失活曲线,模型评价参数(Af,Bf,SS,RMSE和R2)分析表明,Log-Logistic模型比Weibull模型能更好地拟合PEF处理下酿酒酵母失活动力学变化。
基金supported by the National Key Research and Development Program of China (2018YFD0500500)。
文摘African swine fever virus(ASFV)infects domestic pigs and European wild boars with strong,hemorrhagic and high mortality.The primary cellular targets of ASFV is the porcine macrophages.Up to now,no commercial vaccine or effective treatment available to control the disease.In this study,three recombinant Saccharomyces cerevisiae(S.cerevisiae)strains expressing fused ASFV proteins-porcine Ig heavy chains were constructed and the immunogenicity of the S.cerevisiae-vectored cocktail ASFV feeding vaccine was further evaluated.To be specific,the P30-Fcγand P54-Fcαfusion proteins displaying on surface of S.cerevisiae cells were produced by fusing the Fc fragment of porcine immunoglobulin IgG1 or IgA1 with p30 or p54 gene of ASFV respectively.The recombinant P30-Fcγand P54-Fcαfusion proteins expressed by S.cerevisiae were verified by Western blotting,flow cytometry and immunofluorescence assay.Porcine immunoglobulin Fc fragment fused P30/P54 proteins elicited P30/P54-specific antibody production and induced higher mucosal immunity in swine.The absorption and phagocytosis of recombinant S.cerevisiae strains in IPEC-J2 cells or porcine alveolar macrophage(PAM)cells were significantly enhanced,too.Here,we introduce a kind of cheap and safe oral S.cerevisiae-vectored vaccine,which could activate the specific mucosal immunity for controlling ASFV infection.
基金the National Key Research and Development Program of China(2018YFA0902100)National Natural Science Foundation of China(21676190).
文摘Currently,the establishment of synthetic microbial consortia with rational strategies has gained extensive attention,becoming one of the important frontiers of synthetic biology.Systems biology can offer insights into the design and construction of synthetic microbial consortia.Taking the high-efficiency production of 2-keto-L-gulonic acid(2-KLG)as an example,we constructed a synthetic microbial consortium“Saccharomyces cerevisiae-Ketogulonigenium vulgare”based on systems biology analysis.In the consortium,K.vulgare was the 2-KLG pro-ducing strain,and S.cerevisiae acted as the helper strain.Comparative transcriptomic analysis was performed on an engineered S.cerevisiae(VTC2)and a wild-type S.cerevisiae BY4741.The results showed that the up-regulated genes in VTC2,compared with BY4741,were mainly involved in glycolysis,TCA cycle,purine metabolism,and biosynthesis of amino acids,B vitamins,and antioxidant proteases,all of which play important roles in pro-moting the growth of K.vulgare.Furthermore,Vitamin C produced by VTC2 could further relieve the oxidative stress in the environment to increase the production of 2-KLG.Therefore,VTC2 would be of great advantage in working with K.vulgare.Thus,the synthetic microbial consortium"VTC2-K.vulgare"was constructed based on transcriptomics analyses,and the accumulation of 2-KLG was increased by 1.49-fold compared with that of mono-cultured K.vulgare,reaching 13.2±0.52 g/L.In addition,the increased production of 2-KLG was accompanied by the up-regulated activities of superoxide dismutase and catalase in the medium and the up-regulated oxidative stress-related genes(sod,cat and gpd)in K.vulgare.The results indicated that the oxida-tive stress in the synthetic microbial consortium was efficiently reduced.Thus,systems analysis confirmed a favorable symbiotic relationship between microorganisms,providing guidance for further engineering synthetic consortia.
